This chimney pipe from DuraTech contains two steel walls, with a layer of ceramic insulation that helps provide high temperatures on the inside, without causing dangerous heat on the exterior of the piping. This helps promote safety and efficiency when venting any type of heating appliance. This pipe comes in a 7 inch diameter that can easily connect to other piping with the simple twisting lock design. The lifetime warranty ensures that this is a quality product, and the efficient design makes this an easy to use accessory with any heating appliance.